Question: schematics of the analogue output circuit from MiniDSP available?

Hello

I am impressed about your product line and your support skills. Thinking about driving my 2.1 setup by a MiniDSP soon.

But, as I am an "analogue DIYselfer", I am interested in the analog output circuit of the MiniDSP board.

I remark the four caps nearby the output RCA's, thats all.

Can you please publish the analogue part of the circuit?

BTW a feedback about your website: Mostly the orange fonts are not easily readable, be it on white or gray background. I would recommend to change the fonts colour to something with greater contrast to the background.

Unfortunately, we don't plan to publish any schematics for this project. If you were to get this board, you could indeed modify the output stage the way you want but you would be on your own. There is an extend to how much we go into the DIY world, knowing how much we could burn our resources that way. Sometimes hard to realize for end users/DIYers is the fact that answering all these tech inquiries on multiple forums is already quite time consuming. If we were to open the schematics (which honestly, we have no plans to), it would be a can of worms for us having to staff and answer engineering question. Too much load for little return. If you want to build you own input/output stage, DIY your own boards, build your own ADC/DAC stage, I'm afraid that you'll be on your own. Hope you understand even if it may not be the answer you expected.

As for the website, point well taken. We'll try to fix that next week and make it easier to read. Thanks for the feedback.

Thanks for your fast answer! I've also remarked on your website the orange fonts are changed to blue. Much better (many people have problems specially in the red/green area).

Quote:

Unfortunately, we don't plan to publish any schematics for this project. If you were to get this board, you could indeed modify the output stage the way you want but you would be on your own.

As soon as I sold some goods and have the money on paypal, I will order one (or three?) of this boards.

And I am aware, I will be on my own, when I will modify the board.

Quote:

There is an extend to how much we go into the DIY world, knowing how much we could burn our resources that way.

Easy, simply refuse to support modified boards. Please take in mind, I was only asking for the analog path the signal is passing through.

Don't you think, users will quickly do reverse engineering of the mentioned circuit part, as we want to know the signal path when we add own analog circuits, using the D/A capabilities of the MiniDSP board?

It is hard to understand, why you dont want to open documentation for this simple section of the circuit. I cannot imagine a secret circuit but based on some datasheet recommendations. Can you mention us the datasheet?

Quote:

Sometimes hard to realize for end users/DIYers is the fact that answering all these tech inquiries on multiple forums is already quite time consuming.

Sorry, I am an end user but I was also working in the service departement from Studer Professional Audio. I do understand this point of view. Again: simply refuse to support modified boards.

In answer to your questions of why we wouldn't want to release schematics, we really see it as "opening a can of worms"! We start by the analog inputs/outputs, we then get asked for the schematics of the miniAMP, we then get asked for the schematics of the miniDIGI... Where do we stop? What's in for us to give away to potential competitors the work we did building these boards? Although the input/output stage is as you already pointed out basic electronic, it has nothing to do with basic or not, it's more the concept of opening the schematics (even once) which will trigger all the other problems which we don't want to get into. We already have enough on our mind at this point and would rather develop products. :-)

- Can you reverse-engineer a product (and something as simple as an output stage), sure you can as you correctly pointed out and with your experience at Studer, I'm sure that you won't have a problem doing so. Hence the reason why I'm not worried of you succeeding.. :-)
- Are we going to participate into the reverse engineering of our products, not really sure it would benefit our company for the reasons I explained earlier.

Anyways, although once again you may not agree with that point of view, I'm afraid that we're not ready to change our point of view on that one.

I am sure you will again much better fullfill the needs and wishes of the diy community.

Something like this circuit (hardcopy out of the ADAU1701 datasheet)? Or did you use a active filter circuit?

Kind regards
Franz

P.S.
Looking forward to use as starter a 2.1 solution with MiniDSP soon.

/Edit
The advantage for you, to open parts of the circuit to diy community: just look at the success of the Gigawork DAC's in the diy market, mainly based on replacing the analogue audio part by own circuits. Most readers here have skills and tools to manage analogue audio circuits but not digital and DSP programming. I dont have the intention to completely reverse engineer all your boards!

I think the real reason they don't want to release the schematic is because miniDSP is afraid someone might rip off their design. There is really no other reasonable answer as to why you would build a DIY audio kit and not include the schematic. Support is another issue but as Franz Gysi pointed out, just don't support modified boards.

Really though, the ADAU1701 is not a hard IC to work with, in most cases the user can operate in selfboot mode and can design using the free SigmaStudio. Generating a hex and loading it into an EEPROM, although nontraditional because of SigmaStudio method, is easy enough.

If your going through all the trouble of redesigning your output stage, I would recommend just designing your own ADAU1701 board. miniDSP is more of a 'set it and forget it' solution.